<?php

/**
 * @Project NUKEVIET 3.0
 * @Author VINADES.,JSC (contact@vinades.vn)
 * @Copyright (C) 2010 VINADES.,JSC. All rights reserved
 * @Createdate 20/7/2010, 4:53
 */

/**
 * This class provides a simple interface for OpenID (1.1 and 2.0) authentication.
 * Supports Yadis discovery.
 * The authentication process is stateless/dumb.
 *
 * Usage:
 * Sign-on with OpenID is a two step process:
 * Step one is authentication with the provider:
 * <code>
 * $openid = new LightOpenID;
 * $openid->identity = 'ID supplied by user';
 * header('Location: ' . $openid->authUrl());
 * </code>
 * The provider then sends various parameters via GET, one of them is openid_mode.
 * Step two is verification:
 * <code>
 * if ($_GET['openid_mode']) {
 * $openid = new LightOpenID;
 * echo $openid->validate() ? 'Logged in.' : 'Failed';
 * }
 * </code>
 *
 * Optionally, you can set $returnUrl and $realm (or $trustRoot, which is an alias).
 * The default values for those are:
 * $openid->realm     = (!empty($_SERVER['HTTPS']) ? 'https' : 'http') . '://' . $_SERVER['HTTP_HOST'];
 * $openid->returnUrl = $openid->realm . $_SERVER['REQUEST_URI'];
 * If you don't know their meaning, refer to any openid tutorial, or specification. Or just guess.
 *
 * AX and SREG extensions are supported.
 * To use them, specify $openid->required and/or $openid->optional.
 * These are arrays, with values being AX schema paths (the 'path' part of the URL).
 * For example:
 * $openid->required = array('namePerson/friendly', 'contact/email');
 * $openid->optional = array('namePerson/first');
 * If the server supports only SREG or OpenID 1.1, these are automaticaly
 * mapped to SREG names, so that user doesn't have to know anything about the server.
 *
 * To get the values, use $openid->getAttributes().
 *
 *
 * The library depends on curl, and requires PHP 5.
 * @author Mewp
 * @copyright Copyright (c) 2010, Mewp
 * @license http://www.opensource.org/licenses/mit-license.php MIT
 */
class LightOpenID
{

    public $returnUrl, $required = array(), $optional = array();

    private $identity, $claimed_id;

    protected $server, $version, $trustRoot, $aliases, $identifier_select = false, $ax = false, $sreg = false;

    protected static $ax_to_sreg = array(  //
        'namePerson/friendly' => 'nickname', //
		'contact/email' => 'email', //
		'namePerson' => 'fullname', //
		'birthDate' => 'dob', //
		'person/gender' => 'gender', //
		'contact/postalCode/home' => 'postcode', //
		'contact/country/home' => 'country', //
		'pref/language' => 'language', //
		'pref/timezone' => 'timezone', //
		'namePerson/first' => 'firstname', //google - NV
		'namePerson/last' => 'lastname'  //google - NV
    );

    function __construct ( )
    {
        //$this->trustRoot = ( ! empty( $_SERVER['HTTPS'] ) ? 'https' : 'http' ) . '://' . $_SERVER['HTTP_HOST'];
        $this->trustRoot = ( ( isset( $_SERVER['HTTPS'] ) and strtolower( $_SERVER['HTTPS'] ) == 'on' ) ? 'https' : 'http' ) . '://' . $_SERVER['HTTP_HOST'];
        $this->returnUrl = $this->trustRoot . $_SERVER['REQUEST_URI'];
        
        if ( ! function_exists( 'curl_exec' ) )
        {
            trigger_error( 'Curl extension is required.', 256 );
        }
    }

    function __set ( $name, $value )
    {
        switch ( $name )
        {
            case 'identity':
                if ( strlen( $value = trim( $value ) ) )
                {
                    if ( preg_match( '#^xri:/*#i', $value, $m ) )
                    {
                        $value = substr( $value, strlen( $m[0] ) );
                    }
                    elseif ( ! preg_match( '/^(?:[=@+\$!\(]|https?:)/i', $value ) )
                    {
                        $value = "http://$value";
                    }
                    if ( preg_match( '#^https?://[^/]+$#i', $value, $m ) )
                    {
                        $value .= '/';
                    }
                }
                $this->$name = $this->claimed_id = $value;
                break;
            case 'trustRoot':
            case 'realm':
                $this->trustRoot = trim( $value );
        }
    }

    function __get ( $name )
    {
        switch ( $name )
        {
            case 'identity':
                # We return claimed_id instead of identity,
                # because the developer should see the claimed identifier,
                # i.e. what he set as identity, not the op-local identifier (which is what we verify)
                return $this->claimed_id;
            case 'trustRoot':
            case 'realm':
                return $this->trustRoot;
        }
    }

    protected function request ( $url, $method = 'GET', $params = array() )
    {
        $params = http_build_query( $params );
        $curl = curl_init( $url . ( $method == 'GET' && $params ? '?' . $params : '' ) );
        $safe_mode = ( ini_get( 'safe_mode' ) == '1' || strtolower( ini_get( 'safe_mode' ) ) == 'on' ) ? 1 : 0;
        $open_basedir = ( ini_get( 'open_basedir' ) == '1' || strtolower( ini_get( 'open_basedir' ) ) == 'on' ) ? 1 : 0;
        if ( ! $safe_mode and $open_basedir )
        {
            curl_setopt( $curl, CURLOPT_FOLLOWLOCATION, true );
        }
        curl_setopt( $curl, CURLOPT_HEADER, false );
        curl_setopt( $curl, CURLOPT_SSL_VERIFYPEER, false );
        curl_setopt( $curl, CURLOPT_RETURNTRANSFER, true );
        if ( $method == 'POST' )
        {
            curl_setopt( $curl, CURLOPT_POST, true );
            curl_setopt( $curl, CURLOPT_POSTFIELDS, $params );
        }
        elseif ( $method == 'HEAD' )
        {
            curl_setopt( $curl, CURLOPT_HEADER, true );
            curl_setopt( $curl, CURLOPT_NOBODY, true );
        }
        else
        {
            curl_setopt( $curl, CURLOPT_HTTPGET, true );
        }
        curl_setopt( $curl, CURLOPT_TIMEOUT, 30 );
        $response = curl_exec( $curl );
        
        if ( curl_errno( $curl ) )
        {
            trigger_error( 'Curl error: ' . curl_error( $curl ), 256 );
        }
        
        return $response;
    }

    protected function build_url ( $url, $parts )
    {
        if ( isset( $url['query'], $parts['query'] ) )
        {
            $parts['query'] = $url['query'] . '&' . $parts['query'];
        }
        
        $url = $parts + $url;
        $url = $url['scheme'] . '://' . ( empty( $url['username'] ) ? '' : ( empty( $url['password'] ) ? "{$url['username']}@" : "{$url['username']}:{$url['password']}@" ) ) . $url['host'] . ( empty( $url['port'] ) ? '' : ":{$url['port']}" ) . ( empty( $url['path'] ) ? '' : $url['path'] ) . ( empty( $url['query'] ) ? '' : "?{$url['query']}" ) . ( empty( $url['fragment'] ) ? '' : ":{$url['fragment']}" );
        return $url;
    }

    /**
     * Helper function used to scan for <meta>/<link> tags and extract information
     * from them
     */
    protected function htmlTag ( $content, $tag, $attrName, $attrValue, $valueName )
    {
        preg_match_all( "#<{$tag}[^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*$valueName=['\"](.+?)['\"][^>]*/?>#i", $content, $matches1 );
        preg_match_all( "#<{$tag}[^>]*$valueName=['\"](.+?)['\"][^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*/?>#i", $content, $matches2 );
        
        $result = array_merge( $matches1[1], $matches2[1] );
        return empty( $result ) ? false : $result[0];
    }

    /**
     * Performs Yadis and HTML discovery. Normally not used.
     * @param $url Identity URL.
     * @return String OP Endpoint (i.e. OpenID provider address).
     * @throws ErrorException
     */
    function discover ( $url )
    {
        if ( ! $url ) throw new ErrorException( 'No identity supplied.' );
        # Use xri.net proxy to resolve i-name identities
        if ( ! preg_match( '#^https?:#', $url ) )
        {
            $url = "https://xri.net/$url";
        }
        
        # We save the original url in case of Yadis discovery failure.
        # It can happen when we'll be lead to an XRDS document
        # which does not have any OpenID2 services.
        $originalUrl = $url;
        
        # A flag to disable yadis discovery in case of failure in headers.
        $yadis = true;
        
        # We'll jump a maximum of 5 times, to avoid endless redirections.
        for ( $i = 0; $i < 5; $i ++ )
        {
            if ( $yadis )
            {
                $headers = explode( "\n", $this->request( $url, 'HEAD' ) );
                
                $next = false;
                foreach ( $headers as $header )
                {
                    if ( preg_match( '#X-XRDS-Location\s*:\s*(.*)#', $header, $m ) )
                    {
                        $url = $this->build_url( parse_url( $url ), parse_url( trim( $m[1] ) ) );
                        $next = true;
                    }
                    
                    if ( preg_match( '#Content-Type\s*:\s*application/xrds\+xml#i', $header ) )
                    {
                        # Found an XRDS document, now let's find the server, and optionally delegate.
                        $content = $this->request( $url, 'GET' );
                        
                        # OpenID 2
                        # We ignore it for MyOpenID, as it breaks sreg if using OpenID 2.0
                        $ns = preg_quote( 'http://specs.openid.net/auth/2.0/' );
                        if ( preg_match( '#<Service.*?>(.*)<Type>\s*' . $ns . '(.*?)\s*</Type>(.*)</Service>#s', $content, $m ) )
                        {
                            $content = ' ' . $m[1] . $m[3]; # The space is added, so that strpos doesn't return 0.
                            if ( $m[2] == 'server' ) $this->identifier_select = true;
                            
                            preg_match( '#<URI.*?>(.*)</URI>#', $content, $server );
                            preg_match( '#<(Local|Canonical)ID>(.*)</\1ID>#', $content, $delegate );
                            if ( empty( $server ) )
                            {
                                return false;
                            }
                            # Does the server advertise support for either AX or SREG?
                            $this->ax = ( bool )strpos( $content, '<Type>http://openid.net/srv/ax/1.0</Type>' );
                            $this->sreg = strpos( $content, '<Type>http://openid.net/sreg/1.0</Type>' ) || strpos( $content, '<Type>http://openid.net/extensions/sreg/1.1</Type>' );
                            
                            $server = $server[1];
                            if ( isset( $delegate[2] ) ) $this->identity = trim( $delegate[2] );
                            $this->version = 2;
                            
                            $this->server = $server;
                            return $server;
                        }
                        
                        # OpenID 1.1
                        $ns = preg_quote( 'http://openid.net/signon/1.1' );
                        if ( preg_match( '#<Service.*?>(.*)<Type>\s*' . $ns . '\s*</Type>(.*)</Service>#s', $content, $m ) )
                        {
                            $content = ' ' . $m[1] . $m[2];
                            
                            preg_match( '#<URI.*?>(.*)</URI>#', $content, $server );
                            preg_match( '#<.*?Delegate>(.*)</.*?Delegate>#', $content, $delegate );
                            if ( empty( $server ) )
                            {
                                return false;
                            }
                            # AX can be used only with OpenID 2.0, so checking only SREG
                            $this->sreg = strpos( $content, '<Type>http://openid.net/sreg/1.0</Type>' ) || strpos( $content, '<Type>http://openid.net/extensions/sreg/1.1</Type>' );
                            
                            $server = $server[1];
                            if ( isset( $delegate[1] ) ) $this->identity = $delegate[1];
                            $this->version = 1;
                            
                            $this->server = $server;
                            return $server;
                        }
                        
                        $next = true;
                        $yadis = false;
                        $url = $originalUrl;
                        $content = null;
                        break;
                    }
                }
                if ( $next ) continue;
                
                # There are no relevant information in headers, so we search the body.
                $content = $this->request( $url, 'GET' );
                if ( $location = $this->htmlTag( $content, 'meta', 'http-equiv', 'X-XRDS-Location', 'value' ) )
                {
                    $url = $this->build_url( parse_url( $url ), parse_url( $location ) );
                    continue;
                }
            }
            
            if ( ! $content ) $content = $this->request( $url, 'GET' );
            
            # At this point, the YADIS Discovery has failed, so we'll switch
            # to openid2 HTML discovery, then fallback to openid 1.1 discovery.
            $server = $this->htmlTag( $content, 'link', 'rel', 'openid2.provider', 'href' );
            $delegate = $this->htmlTag( $content, 'link', 'rel', 'openid2.local_id', 'href' );
            $this->version = 2;
            
            if ( ! $server )
            {
                # The same with openid 1.1
                $server = $this->htmlTag( $content, 'link', 'rel', 'openid.server', 'href' );
                $delegate = $this->htmlTag( $content, 'link', 'rel', 'openid.delegate', 'href' );
                $this->version = 1;
            }
            
            if ( $server )
            {
                # We found an OpenID2 OP Endpoint
                if ( $delegate )
                {
                    # We have also found an OP-Local ID.
                    $this->identity = $delegate;
                }
                $this->server = $server;
                return $server;
            }
            
            trigger_error( 'No servers found!', 256 );
        }
        trigger_error( 'Endless redirection!', 256 );
    }

    protected function sregParams ( )
    {
        $params = array();
        # We always use SREG 1.1, even if the server is advertising only support for 1.0.
        # That's because it's fully backwards compatibile with 1.0, and some providers
        # advertise 1.0 even if they accept only 1.1. One such provider is myopenid.com
        $params['openid.ns.sreg'] = 'http://openid.net/extensions/sreg/1.1';
        if ( $this->required )
        {
            $params['openid.sreg.required'] = array();
            foreach ( $this->required as $required )
            {
                if ( ! isset( self::$ax_to_sreg[$required] ) ) continue;
                $params['openid.sreg.required'][] = self::$ax_to_sreg[$required];
            }
            $params['openid.sreg.required'] = implode( ',', $params['openid.sreg.required'] );
        }
        
        if ( $this->optional )
        {
            $params['openid.sreg.optional'] = array();
            foreach ( $this->optional as $optional )
            {
                if ( ! isset( self::$ax_to_sreg[$optional] ) ) continue;
                $params['openid.sreg.optional'][] = self::$ax_to_sreg[$optional];
            }
            $params['openid.sreg.optional'] = implode( ',', $params['openid.sreg.optional'] );
        }
        return $params;
    }

    protected function axParams ( )
    {
        $params = array();
        if ( $this->required || $this->optional )
        {
            $params['openid.ns.ax'] = 'http://openid.net/srv/ax/1.0';
            $params['openid.ax.mode'] = 'fetch_request';
            $this->aliases = array();
            $counts = array();
            $required = array();
            $optional = array();
            foreach ( array( 
                'required', 'optional' 
            ) as $type )
            {
                foreach ( $this->$type as $alias => $field )
                {
                    if ( is_int( $alias ) ) $alias = strtr( $field, '/', '_' );
                    $this->aliases[$alias] = 'http://axschema.org/' . $field;
                    if ( empty( $counts[$alias] ) ) $counts[$alias] = 0;
                    $counts[$alias] += 1;
                    ${$type}[] = $alias;
                }
            }
            foreach ( $this->aliases as $alias => $ns )
            {
                $params['openid.ax.type.' . $alias] = $ns;
            }
            foreach ( $counts as $alias => $count )
            {
                if ( $count == 1 ) continue;
                $params['openid.ax.count.' . $alias] = $count;
            }
            $params['openid.ax.required'] = implode( ',', $required );
            $params['openid.ax.if_avaiable'] = implode( ',', $optional );
        }
        return $params;
    }

    protected function authUrl_v1 ( )
    {
        $returnUrl = $this->returnUrl;
        # If we have an openid.delegate that is different from our claimed id,
        # we need to somehow preserve the claimed id between requests.
        # The simplest way is to just send it along with the return_to url.
        if ( $this->identity != $this->claimed_id )
        {
            $returnUrl .= ( strpos( $returnUrl, '?' ) ? '&' : '?' ) . 'openid.claimed_id=' . $this->claimed_id;
        }
        
        $params = array( 
            'openid.return_to' => $returnUrl, 'openid.mode' => 'checkid_setup', 'openid.identity' => $this->identity, 'openid.trust_root' => $this->trustRoot 
        ) + $this->sregParams();
        
        return $this->build_url( parse_url( $this->server ), array( 
            'query' => http_build_query( $params ) 
        ) );
    }

    protected function authUrl_v2 ( $identifier_select )
    {
        $params = array( 
            'openid.ns' => 'http://specs.openid.net/auth/2.0', 'openid.mode' => 'checkid_setup', 'openid.return_to' => $this->returnUrl, 'openid.realm' => $this->trustRoot 
        );
        if ( $this->ax )
        {
            $params += $this->axParams();
        }
        if ( $this->sreg )
        {
            $params += $this->sregParams();
        }
        if ( ! $this->ax && ! $this->sreg )
        {
            # If OP doesn't advertise either SREG, nor AX, let's send them both
            # in worst case we don't get anything in return.
            $params += $this->axParams() + $this->sregParams();
        }
        
        if ( $identifier_select )
        {
            $params['openid.identity'] = $params['openid.claimed_id'] = 'http://specs.openid.net/auth/2.0/identifier_select';
        }
        else
        {
            $params['openid.identity'] = $this->identity;
            $params['openid.claimed_id'] = $this->claimed_id;
        }
        
        return $this->build_url( parse_url( $this->server ), array( 
            'query' => http_build_query( $params ) 
        ) );
    }

    /**
     * Returns authentication url. Usually, you want to redirect your user to it.
     * @return String The authentication url.
     * @param String $select_identifier Whether to request OP to select identity for an user in OpenID 2. Does not affect OpenID 1.
     * @throws ErrorException
     */
    function authUrl ( $identifier_select = null )
    {
        if ( ! $this->server ) $this->discover( $this->identity );
        
        if ( $this->version == 2 )
        {
            if ( $identifier_select === null )
            {
                return $this->authUrl_v2( $this->identifier_select );
            }
            return $this->authUrl_v2( $identifier_select );
        }
        return $this->authUrl_v1();
    }

    /**
     * Performs OpenID verification with the OP.
     * @return Bool Whether the verification was successful.
     * @throws ErrorException
     */
    function validate ( )
    {
        $this->claimed_id = $_GET['openid_claimed_id'];
        $params = array( 
            'openid.assoc_handle' => $_GET['openid_assoc_handle'], 'openid.signed' => $_GET['openid_signed'], 'openid.sig' => $_GET['openid_sig'] 
        );
        
        if ( isset( $_GET['openid_op_endpoint'] ) )
        {
            # We're dealing with an OpenID 2.0 server, so let's set an ns
            # Even though we should know location of the endpoint,
            # we still need to verify it by discovery, so $server is not set here
            $params['openid.ns'] = 'http://specs.openid.net/auth/2.0';
        }
        $server = $this->discover( $_GET['openid_identity'] );
        
        foreach ( explode( ',', $_GET['openid_signed'] ) as $item )
        {
            # Checking whether magic_quotes_gpc is turned on, because
            # the function may fail if it is. For example, when fetching
            # AX namePerson, it might containg an apostrophe, which will be escaped.
            # In such case, validation would fail, since we'd send different data than OP
            # wants to verify. stripslashes() should solve that problem, but we can't
            # use it when magic_quotes is off.
            $value = $_GET['openid_' . str_replace( '.', '_', $item )];
            $params['openid.' . $item] = get_magic_quotes_gpc() ? stripslashes( $value ) : $value;
        }
        
        $params['openid.mode'] = 'check_authentication';
        
        $response = $this->request( $server, 'POST', $params );
        
        return preg_match( '/is_valid\s*:\s*true/i', $response );
    }

    protected function getAxAttributes ( )
    {
        $alias = null;
        if ( isset( $_GET['openid_ns_ax'] ) && $_GET['openid_ns_ax'] != 'http://openid.net/srv/ax/1.0' )
        { # It's the most likely case, so we'll check it before
            $alias = 'ax';
        }
        else
        {
            # 'ax' prefix is either undefined, or points to another extension,
            # so we search for another prefix
            foreach ( $_GET as $key => $val )
            {
                if ( substr( $key, 0, strlen( 'openid_ns_' ) ) == 'openid_ns_' && $val == 'http://openid.net/srv/ax/1.0' )
                {
                    $alias = substr( $key, strlen( 'openid_ns_' ) );
                    break;
                }
            }
        }
        if ( ! $alias )
        {
            # An alias for AX schema has not been found,
            # so there is no AX data in the OP's response
            return array();
        }
        
        foreach ( $_GET as $key => $value )
        {
            $keyMatch = 'openid_' . $alias . '_value_';
            if ( substr( $key, 0, strlen( $keyMatch ) ) != $keyMatch )
            {
                continue;
            }
            $key = substr( $key, strlen( $keyMatch ) );
            if ( ! isset( $_GET['openid_' . $alias . '_type_' . $key] ) )
            {
                # OP is breaking the spec by returning a field without
                # associated ns. This shouldn't happen, but it's better
                # to check, than cause an E_NOTICE.
                continue;
            }
            $key = substr( $_GET['openid_' . $alias . '_type_' . $key], strlen( 'http://axschema.org/' ) );
            $attributes[$key] = $value;
        }
        # Found the AX attributes, so no need to scan for SREG.
        return $attributes;
    }

    protected function getSregAttributes ( )
    {
        $attributes = array();
        $sreg_to_ax = array_flip( self::$ax_to_sreg );
        foreach ( $_GET as $key => $value )
        {
            $keyMatch = 'openid_sreg_';
            if ( substr( $key, 0, strlen( $keyMatch ) ) != $keyMatch )
            {
                continue;
            }
            $key = substr( $key, strlen( $keyMatch ) );
            if ( ! isset( $sreg_to_ax[$key] ) )
            {
                # The field name isn't part of the SREG spec, so we ignore it.
                continue;
            }
            $attributes[$sreg_to_ax[$key]] = $value;
        }
        return $attributes;
    }

    /**
     * Gets AX/SREG attributes provided by OP. should be used only after successful validaton.
     * Note that it does not guarantee that any of the required/optional parameters will be present,
     * or that there will be no other attributes besides those specified.
     * In other words. OP may provide whatever information it wants to.
     * * SREG names will be mapped to AX names.
     * * @return Array Array of attributes with keys being the AX schema names, e.g. 'contact/email'
     * @see http://www.axschema.org/types/
     */
    function getAttributes ( )
    {
        $attributes;
        if ( isset( $_GET['openid_ns'] ) && $_GET['openid_ns'] == 'http://specs.openid.net/auth/2.0' )
        { # OpenID 2.0
            # We search for both AX and SREG attributes, with AX taking precedence.
            return $this->getAxAttributes() + $this->getSregAttributes();
        }
        return $this->getSregAttributes();
    }
}

?>